Dissolution mechanism of cellulose in SO2–amine–dimethylsulfoxide

The dissolution mechanism of cellulose in SO2–amine–dimethylsulfoxide systems was studied by using 1H- and 13C-NMR spectroscopy. SO2 and amine (diethylamine or triethylamine) were found to form a complex in DMSO, and the SO2–amine complex, in turn, reacts with an alcoholic hydroxyl group of methanol to produce a new complex. In the case of cellulose, it was proved that all hydroxyl groups in cellulose react with the SO2–amine complexes and form the same complexes in the solution state as those formed in methanol.